Cast for orthopedic use



Jan. 15, 1952 J. J. EBERL 2,582,242

CAST FOR ORTHOPEDIC USE Filed Nov. 29, 1947 7702 Una/405E INVENTOR JwisJ 555:4. w/fwioml...

ATTORN EY Patented Jan. 15, 1952 "Ty UNITED" STATES TEN OFFICE "JamesJoseph Eberl, Piscataway Township, Middlcsex County, N. J., assignor toJohnson & Johnson, a corporation of New Jersey I Application November29, 1947, Serial No. 788,970

6 Claims. (Cl-112M90 This invention relates to'improved'resin casts;

for orthopedic use and to a process of forming,

the sameand is concerned particularly with casts that are applied fromsolvent In the past, orthopedic casts were usually based on plaster ofParis which was mixed with water in the form of a heavy paste, appliedto a body member and allowed to set, but more recentlya type of bandagehas become available wherein a porous web, e. g. crinoline, impregnatedwith particles of plaster of Paris, is dipped in water for I a fewseconds, then wrapped around the body member and allowed to set.Although plaster of Paris bandages are used extensively they havecertain important disadvantages such as undue weight andhigh bulk, ahigh degree of X-ray,

opacity, and imporousness The heavy weight and high bulk of plaster ofParis bandages are disadvantages in casts that are worn by ambu-latorypatients, the X-ray opacity prevents ob servation by the physician ofcallus formation-'- and the imporousness of plaster of Paris casts'jprevents "breathing of the wound or elimination of perspiration and isaccordingly responsible for-some of the disagreeable odor that is sooften associated with casts that have been worn for long periods oftime. Moreover, plaster of Paris does not reach its maximum strengthdur-, ing its setting process until one or two days after applicationand the amount of heat that is given off by thecast during its initialsetting make the cast uncomfortable to the patient. I In view of theabove-mentioned disadvantages of plaster of Paris casts, bandages basedon synthetic or natural resins-have been under development for sometime. Their use requires application by wetting of the bandage withsolvent, bandaging of the patient, and evaporation of thesolvent as thecast dries out and gains its strength. In the past development of thistype of cast, the resins used and the type of cast,

desired necessitated the use of highly toxicor inflammable organicsolvents. To many patients and physicians the disadvantages inherent inthe use of these solvents outweighed the advantages to be gained byusing casts based on materials other than plaster of Paris. In one case,death of a patient was reportedly due to the action or the solvent usedmapplication of the cast. Prior to the invention, surgical casts basedon resins. or polymers that would not require use of toxic orinflammable solvents were not used.

This invention provides a means of applyingv bandages comprising highpolymers wherein there are used solvents that aresubstantlall tree oftoxicity and is based uponthe discovery that chlorofluoroparafiins thatare liquid at normal room temperatures and that boil at temperaturesbetween 35 and 85* C. in admixture with mutual solvents for ethylcelulose and chlorofluoroparaifins', form satisfactory solvents forethyl cellu lose.

Other objects andadvantages of the invention will be apparent from thefollowing description of practical embodiments thereof, furnished by wayof example only and not in' order to limit the invention, particularlywhen considered in connection with the drawing wherein:

Fig. 1. is a view in perspective of a resin cast iii-accordance with theinvention made from an orthopedic bandage as described herein;

Fig. 2 is a view in perspective of a roll of ortho pedic bandage made inaccordance with their!- vention; a

Fig. 3 is an enlarged plan view sho'winga small part of anorthopedic-bandage made in accordance with the invention.

In carrying the invention into practice, fibrous material not greatporosity (e. g. crinoline-of wide mesh) is impregnated with ethylcellulose l3 so as to provide a bandage composed of a major proportion,by weight, of ethyl cellulose. l'he bandage is activated by wetting withanon toxic, non-irritant solvent mixture therefor comprising a majorproportion by weight of a liquid chlorofluoroparafiin and a minorproportionof a mutual solvent for ethyl cellulose and chloro-I'luoroparaflin. At least 3% mutual solvent, based on the. totalweightof the solvent mixture, is necessary to provide sufficient solubilityforthe ethyl cellulose in the solvent. The wetted bandage is applied bywrapping it around'the bcdy member and on evaporation of the solvent arigid, well-laminated cast'results. "This cast is of light weight andlow bulk and exceeds in strength a cast of comparable weight made fromplaster of Paris. The orthopedic bandage made according to theinventionmay' be coiled into a roll H as illustrated in Fig. 2 and isapplied normally to form an orthopedic cast H] as illustrated in, Fig.1.

While any of the various available typesoi ethyl cellulose may be usedin executingthe in vention, ethyl cellulose having an ethoxyl content ofbetween 45 and 50% by weight and a viscosity of 10 centipoises or lessin a solution comprising 5% ethyl cellulose in parts by weight oitoluene and 20 parts by weight of ethyl alcohol is preferred becausethis type of ethyl cellulose is most readily wetted by the solvent andrequires The fibrous material base ma comprisean of the well-knownweb-forming fibrous materials such as cotton, rayon, linen, etc. Itis'preferable that the fibrous material be in the form of a fairly openwoven gauze, of cheese cloth, or of to- 2,582,242 iii materials can beaccurately measured and may be placed in a sealed container, as forexample a tin can in which they may be stored for use I by thephysician.

In order to disclose the nature of the present invention more clearly, apreferred embodiment thereof will now be described in considerabledetail; It is to 'beunderstood; however, that this is done merely by wayof example and-solely for the purpose of illustrating by means of aspecific example the basic principles which are broadly I .applicable toall the embodiments contemplated bythe invention. In other words, theinvention is not restricted in any way to the specific exbacco cloth.The ethyl cellulosemay be applied to the web in the form of an emulsion,or ethyl cellulose fibers may be interwoven with the other fibrousmaterial. The mesh of the bandage is adjusted so that substantialstrength and'good porosity are obtained. I 1

The principal component of the solvent is a chlorofluoroparaflinpreferably one having 5 or less carbon atoms in the'molecule and eitherin itself having a boiling point in the range of 35-85 C. or, in anycase, adapted to provide a mixture having a boiling point within thatrange when combined with a minor portion of a mutual solvent for boththe chlorofluoroparafiin and the ethyl cellulose. Variouschlorofiuoroparamns may be combined to produce a solvent compositionthat complies with the above specification and all such solventcompositions are included in the inventive concept, By way of exampleonly, the following chlorofiuoroparafiins may be utilized:'1-monochloro-2,'2-1difluoroethane, any trichlorotrifiuoroethane,l-monochloro2,2-difluoropropane, 2-monochloro-3,3-difiuciropropane,1-monochloro-3,3-trifiu0ropropane, 1,2-dichloro- 1,1-difluoropropane,l,1-dichloro-3,3,3-trifluoropropane,1,2-dichloro-1,1,2-trifiuoropropane, 1,2-dichloro-3,3,3-trifiuoropropane, 1,2dichlor o-1,l,2,-3,-3,3-hexafluoropropane, 1,1,2-trichloro-1,2- difiuoropropane,1,1,2-trichloro-l,2,3,3,3-pentafluoropropane,l,l,2,3-tetrachloro-1,3,3-trifluoropropane,2-monochloro-2-monofluorobutane, 2- monochloro-3,3-difluorobutane,2-monochloro- 2,3,3-trifluorobutane, and 1,l,1-trichloro-2,2,3',3-tetrafluorobutane. In general, all chlorofiuoroparaffins falling withinthe specifications given earlier in thisdescriptiom'are satisfactorysolvents for ethyl cellulose provided they are used in admixture withminor proportions of lower alcohols, esters, ethers or ketones or othermutual solvents. Among the mutual solvents, use is'made preferably ofethyl alcohol but methyl or propyl .alcohol or butyl alcohol and relatedalcohols, esters and/or ketones having eight or less carbon atoms in themolecule can be used. The advantage of ethyl alcohol is its relativelylow toxicity and the relatively small proportion necessary to effectsatisfactory wetting ofethyl cellulose. These two factors combine toprovide maximum safety for patient and physician. Examples of estersthat work satisfactorily are methyl acetate, ethyl acetate, propylacetate, butyl acetate, ethyl propionate, butyl propionate; of ethers,ethyl ether and propyl ether; vof ketones, acetone, methyl ethyl ketone,methyl isopropyl ketone, di-isopropyl ketone and mesityl amplehereinafter described.

, I Example An open mesh,g auze-type cotton cloth having from five totwenty openings to the inch in each direction was impregnated with anethyl cellulose emulsion comprising:

- Parts Ethyl cellulose. 50 Xylene 84 Butanol 14-.

Water 99 Sorbitol mono-oleate wetting agent"; 2 Dioctyl ester of sodiumsulfosuccinic acid 1 In preparing the emulsionthe ethyl cellulose wasfirst dissolved in the mixed solvent and the wetting agent then added.-This solution was heated on a steam bath and added under rapid stirringto a hot'aqueous solution of the sulfosuccinate. The emulsion thickenedsomewhat on cooling and was applied tothe cloth by a spreading action aswith a knife spreader. The bandage was then dried in an oven and wasfound to contain approximately six parts by weight of ethyl cellulosesolids and approximately four parts of base 'cloth. I

In use, the bandage was immersed in about 2 times its weight of asolution'of ninety parts of trichlorotrifluoroethane and ten parts ofethyl alcohol. The bandage was then wound around a body member andallowed to set, preferably by directing thereon a .warm air blower.across the surface thereof. The bandage hardened substantially in lessthan one-half hour and was completely dried in about three hours. 1 vWhile in the above example-the ethyl cellulose was applied in the formof an emulsion, it may be applied with good results by other methodssuch as by solvent or hot melt coating. The sol: vent mixture used maybe composed of any chlorofiuoroparaflin, and particularly of any ofthose listed earlierin this specification, and may comprise. any loweralcohol, ester or ketone as above defined provided the, boilingpoint ofthe resulting solvent mixture is in the range of 35-85 0. 3-15 of themutual solvent andthe remainder chlorofluoroparafiin are preferred inthe solvent composition. The casts may be canned. in the solvent orstored separately from the solvent and wetted thereby immediately priorto application. In the first few minutes of drying, plaster casts havegreater strength than comparable resin'casts of the type disclosed inthe invention, but as drying proceeds the resin casts of r the inventiongain strength more rapidly than plaster casts and exceed the lattermaterially in strength. Tests indicate that after about 3 /2 hours ofdrying time, casts prepared. according to the invention are highlysuperior in strength to plaster of Pariscasts of the same weight. Resincasts having three to four times the strength of comparable plastercasts were obtained in accordance with this invention. Much lightercasts attain strength equal to that of the heavier plaster casts.Moreover, the cast of the present invention is not only lighter inweight but also highly permeable to air and its use permits ready escapeof perspiration from the body member in the cast.

All embodiments within the scope of this specification and/or theappended claims are comprehended in the invention. Many modificationsmay be made without departing from the spirit and scope of theinvention. All variations and modifications are to be understood asincluded within the scope of the following claims.

The claims are:

1.- The process of applying to a body an orthopedic cast characterizedby having a base comprising a porous fabric impregnated with ethylcellulose, the steps of activating said ethyl cellulose in the fabric bywetting with a solvent composition boiling in the range of 35-85 C. andcomprising a major proportion by weight of a chlorofiuoroparafiin and aminor proportion, less than fifteen per cent by weight, of a mutualsolvent for said chlorofluoroparaffin and said ethyl cellulose andselected from the group consisting of the lower alcohols, esters,ethers, and ketones having eight or less carbon atoms per molecule, andapplying said impregnated and activated fabric to a body, permitting thesolvent composition to evaporate.

2. The process of applying to a body an orthopedic cast characterized byhaving a base comprising a light weight porous fabric having from 5 to20 strands to the inch in each direction impregnated with ethylcellulose to the extent of 50-75 per cent by weight of the finishedproduct, the steps of activating said ethyl cellulose in the fabric bywetting using a solvent composition boiling in the range of 35-85 C.,and comprising a major proportion of trichlorotrifiuoroethane and aminor proportion, less than fifteen per cent by weight, of ethylalcohol, applying said impregnated and activated fabric to a body andpermitting said solvent composition to evaporate from said fabric.

3. The process of applying to a body an orthopedic cast characterized byhaving a base comprising a light weight porous fabric impregnated withethyl cellulose, the steps of activating said ethyl cellulose in thefabric by wetting with a solvent composition that is liquid at normalroom temperatures, boils in the range of 35-85 0., and comprises a majorproportion of chlorofiuoroparafiin and a minor proportion, less than 15per cent by weight of said solvent composition, of an alcohol solventfor said chlorofluoroparafiln and said ethyl cellulose and applying saidimpregnated and activated fabric to a body, permitting said solventcomposition to evaporate from said fabric.

4. The process of applying to a body an orthopedic cast characterized byhaving a base comprising a light weight porous fabric having from 5 to20 strands to the inch in each direction impregnated with ethylcellulose to the extent of 50-75 per cent by weight of the finishedtreated fabric, the steps of activating said ethyl cellulose in thefabric by wetting it with a solvent composition that is liquid at normalroom temperatures, boils in the range of 35-85 C., and comprises a majorproportion by weight of a chlorofluoroparaffin and a minor proportion,less than fifteen per cent by weight, of a mutual solvent for saidchlorofluoroparaifin and said ethyl cellulose and selected from thegroup consisting of the lower alcohols, esters, ethers, and ketoneshaving eight or less carbon atoms per molecule, and applying saidimpregnated and activated fabric to a body, permitting said solventcomposition to evaporate from said fabric.

5. The process of applying to a body an orthopedic cast characterized byhaving a base comprising a light weight porous fabric impregnated to theextent of 50-75 per cent by weight of the finished treated fabric withethyl cellulose having an ethoxyl content between 45 and 50 per cent anda viscosity of not more than 10 centipoises when in solution comprising5 per cent ethyl cellulose in parts by weight of toluene and 20 parts byweight of ethyl alcohol, the steps of activating said ethyl cellulose inthe fabric by wetting it with a solvent composition comprising a majorproportion of trichlorotrifluoroethane and a minor proportion, 3-15 percent of the weight of said solvent composition, of ethyl alcohol,applying said impregnated and activated fabric to a body and permittingsaid solvent composition to evaporate from said fabric.

6. In the process of applying to a body an orthopedic cast characterizedby having a base comprising a light weight porous fabric impregnatedwith ethyl cellulose, the step of activating said ethyl cellulose in thefabric by wetting with a solvent composition boiling in the range of35-85 C. and comprising a major proportion by weight of achlorofiuoroparaflin and a minor proportion, less than'fifteen per centby weight, of a mutual solvent from said chlorofiuoroparafiin and saidethyl cellulose and selected from the group consisting of the loweralcohols, esters, ethers, and ketones having eight or :less carbon atomsper molecule.

JAlVIES JOSEPH EBERL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,077,874 Brower Apr. 20, 19372,218,844 Lovell Oct. 22, 1940 2,254,469 Bjorksten Sept. 2, 19412,292,531 Lovell Aug. 11, 1942 2,373,802 Anderson Apr. 17, 19452,381,753 Irion Aug. 7, 1945

